Valve-gear.



H. SANDBRSON, R. J. ISAAUSON & H. SI. J. SANDERSON.

VALVE GEAR.

APPLIOATION FILED MAR. 14, 1908,

Patented Mar. 16, 1909.

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UNITED STATES ranncr error.

HORACE SANDFRSON, OF BEN RHYDDING, RUPERT JOHN ISAACSON, OF ILRLEY, ANDHEN RY ST. JOHN SANDERSON, OF BEN RHYDDING, ENGLAND.

VALVE-GEAR.

Specification of Letters Patent.

Patented March 16, 1909.

Application filed March 1 2, 1908. Serial llo. 421,051.

T 0 all whom it may concern:

Be it known that we, Hermon SANDERSON, RUPERT JonN ISAACSON, and HENRYST. JOHN Sannnnsox, subjects of the King of Great Britain and Ireland,residing, respec tively, at Ben Rhydding, llkley, and Ben Rhydding, inthe county of York, England, have invented Improvements in Valve-Gearsfor Steam and other Fluid-Pressure Engines, of which the following is aspecification.

This invention has reference to improvements in valve gears for steamand other fluid pressure engines and more particularly to valve gears oflocomotive engines.

It is desirable to so operate the valve of a steam engine that the valveshall move quickly to fully open the admission port at an early point ofthe stroke of the piston, remain open for a considerable period andclose quickly. It is also desirable that the valve shall be operated toopen and close the steam ports in the same manner and at the same pointsof the stroke of the piston at both ends of the cylinder, and,particularly in the case of engines which are reversed for considerableperiods, that the ports shall be opened and closed at the same points ofthe piston strokes whichever way the engine be running. Furthermore, inlocomotive engines having inside cylinders, owing to the limited spacebetween the engine frames, it.

is necessary that the gear be such that it can be made correspondinglynarrow.

The gear forming the subject of this application has been designed withthese points in view and is thought to more nearly meet theserequirements than gears heretofore constructed.

According to this invention, aslotted. link in which is a movable dieconnected to the valve rod, is actuated by means of two eccentrics, therods of which are connected to the slotted link respectively at one end,or thereabout, and at a point more remote from that The link issupported by an oscillatory arm which embraces the connecting rod pivotat or near the end of the link (or a pivot coaxial therewith) andextends across the link to a pivotal point of support, the slotted linkthus mounted being capable of being oscillated about either of thetwopoints by the two eccentrics.

The point of support of the oscillatory arm, especi ly i e case ofengines w ich ar frequently reversed, may be adapted to j be shiftedduring reversal in such manner as to maintain the points of admissionand cut off practically or nearly constant at both ends of the cylinderfor forward and backard running of the engine. T 1e point of support ofsuch oscillatory arm may be outside the center of the main reversingshaft so as to be cii'cumferentially adjusted there about, such radialadjustment being governed by the movement of the reversing lever whilealtering the position of the die and end of valve rod from one end ofthe slot in the link to the other end for reversing purposes, andintermediate positions therein.

6 will now proceed to describe the invention by the aid of theaccompanying illustrative drawings, in which Figures 1 and 2 arerespectively a plan view and side elevation of one construction of valvegear according to this invention suitablefor a locomotive engine. Fig.is a sectional end view showing the method of suspending the slottedlink. Figs. 4 and 5 are respectively a side elevation and an end viewshowing another method of suspending the said link. Figs. 6 to S aredetail views hereinafter referred to.

In one construction of valve gear according to this invention suitablefor a locomotive engine, the center of the link a is placed, ifanything, forward of the center of the reversing shaft l) which isarranged transversely above it and has secured to it the main lever bthe movement of which causes reversal. The boss 0 of the reversing lever(Z, which is linked to the valve rodf, surrounds such shaft 1), and isformed on its lower side g, at right angles to the said lever arm (Z,with a projecting lug h, which may be the same thickness as the boss andhas, at a certain distance from the center of the lever cl, a, bearing ifor a stud 7r on the projecting ends Z and Z of which are mounted a pairof oscillating arms m having bearings a in their lower ends 0 to receivea joint pin 30 which also passes through a suitable bearing '1' in thelo er ends 8 of the link a and forms the joint pin for one end of aneccentric rod a, the strap 1) of which surrounds an eccentric in that issecured on the crank shaft a and is adapted to give sufiicicnt motion tothe link a to operate the valve in either direction to fully open theadmission ports. The position of this bearing r in the lower end 8 ofthe link a may conveniently be on a straight line 'y@ passing through orpractically through the outer corners z of the elongated slot 1 formedin the link a, and at a suitable distance from the center 2 of the-linka; or it may as shown in Fig. 6 be on a horizontal line 3 drawn at rightangles to a vertical line 4 passing through the center 2 of the lengthof the link a, the line 3 passing through the junction of the line 4 andthe curved center line of the slot 1. of the link a. Another bearing 6is formed in the back portion 7 of the link a at a certain distance fromthe center 2 of the radial slot 1, also on the horizontal center line atand in this bearing 6 is placed the joint pin 8 of an eccentric rod 9,the strap 10 of which surrounds an eccentric 11. that is secured on thecrank-shaft .r at 180 to the crank 12 and has a throw equal to the lapand lead, so that the valve will receive sufficient movement through thelink a, to open. either port to lead. Vi hen the crank 12 is on the deadcenter the first eccentric w is fixed in the requisite angular positionwith the crank 12 and the second eccentric 11.

When the engine is running in the forward direction with the reversinglever or arm d in its lowest position, the valve rod die 13, being inthe lower end 14 of the slot 1, the link a will be in the verticalposition, the center of the )rojecting lug 72, on the reversing lever clbe llllCl the center of the reversing shaft 1), and the back port opento lead. The action of the first named eccentric to then will move thebearing 1' in the lower end 8 of the link a forward and oscillate thelink a on the stud 8 of the second named eccentric rod 9 and fully openthe port; the combined action of both eccentrics w and 11 acting on thelink a then causes the valve to dwell for a certain time, and then toclose the back port, when the second eccentric 11 so oscillates the linka on the pin 19 of the first eccentric w, as to open the front port tolead, when similar movements of the link a and valve take place.

The movement of the support of the oscillatory arms m into the positionbehind the center of the reversing shaft 1 (Fig. 2), slightly lifts thelink a owing to the circumferential movement of the stud 1c about thereversing shaft Z), imparts such an angular movement to the link a thatthe lower end 8 thereof is moved in a forward direction, with the resultthat the combined action of the two eccentrics w and 11 on the link agives to the valve a properly balanced movement so that it cannotoverrun the port at the back end of its movement. hen the reversinglever or arm (Z ismoved to the other end of its movement and the die 13of the valve rod f placed in the upper end 15 of the slot 1, the support7c of the oscillatory arms m is moved in front of the center of thereversing shaft 6, which puts the said arms mnearly in a verticalposition and produces an angular moveme'nt of the lower end 8 of thelink a in the re verse direction, and insures a properly balancedmovement of the valve in this case also.

Other methods of altering the position of the support of the oscillatoryarms may be adopted, such as making the ends 16 of the reversingshaft 1) eccentric with the body part, as shown in Figs. 4 and 5, suchends being mounted in bearings on the engine frame; the ends 17 of theoscillatory arms m then surround the reversing shaft 1).

In the case of locomotive engines with outside cylinders, one of theeccentrics may be placed on the outer end of the crank shaft :r, orinstead of an eccentric, a return crank may be used. Instead ofconnecting the first named eccentric rod to to the joint pin p in thelower end s of the link a it may be connected to the oscillatory arms min any convenient position above the said pin 2) without altering themovement of the link a, the throw of the eccentric being altered to suitthe required movement of the arms.

When curved unslotted bars are used in stead of the slotted link, as inthe case of marine engines, as shown in Figs. 6 and 7 the bars 18 may besecured to suitable side'plates 19 by bolts 20, and spaced apart bypillar bolts 21, such side plates 19 being provided with the necessarybearings for the connections of the eccentrics and oscillatory arms m asin the case of the slotted linka. Or such plates may be made in onepiece with the bars 18 as shown in Fig. 8.

hen the reversing lever is made in one piece with the reversing shaft asuitable lug or boss is or may be formed thereon to receive the stud orsupport of the oscillatory arms instead of the projecting lug beingformed on the reversing lever d.

In engines which are seldom reversed, the support of the oscillatoryarms may be fixed, for instance the reversing shaft may extend throughtheir upper ends, but such an arrangement is not so advantageous asregards efficiency, when the engine is reversed, and cheapness ofconstruction.

Although an arrangement in which the reversing lever is above the linkand the oscillatory arms are pendulous has been described it is to beunderstood that the gear may be otherwise arranged, for instance itmight be turned over so that the reversing shaft would be below insteadof above.

What we claim is 1. In a valve-gear for fluid-pressure engines embodyinga valve reciprocated by two eccentricsone of which has a throwcorresponding to the lap and lead of the valve and the other a throwcorresponding to the full opening of the valve, an oscillating link towhich the rods of said eccentrics are respectively connected atdifferent points, the connection of the eccentric rod giving the fullopening of the valve being at the lower end of the link, a reversingrock-shaft journaled above the link and provided with a reversing leverand means connecting the same to the shifting portion of the valve-rod,a supporting link pivotally connected at its lower end to the lower endof the oscillating link on the same stud as the end of the connectingrod of the eccentric which gives the full opening to the valve and meanspivotally connecting its upper end to the reversing lever, the axis ofthis pivot being arranged horizontally underneath the reversing shaft soas to be shifted alternately forward of and behind the center of therock-shaft when the engine is reversed by rocking the reversing shaft.

2. In a valve-gear for fluid-pressure engines embodying a valvereciprocated by two eccentrics one of which has a throw corresponding tothe lap and lead of the valve and t e other a throw corresponding to thefull opening of the valve, an oscillating link to which the rods of saideccentrics are respectively connected at different points, theconnection of the eccentric rod giving the full opening of the valvebeing at the lower end of the link, a reversing rock-shaft ournaledabove the link and provided with a reversing lever and means connectingthe same to the shifting portion of the valve-rod, a supporting linkpivotally connected at its lower end to the lower end of the oscillatinglink on the same stud as the end of the connecting rod of the eccentricwhich gives the full opening to the valve, and means pivotallyconnecting its upper end to the reversing lever, said means embodying adepending arm or lug carrying a pivot stud whose axis is below andparallel with the axis of the reversing shaft, this pivot being solocated that it shifts to points forward of and behind the axis of thereversing shaft when the engine is reversed.

Signed at Leeds, England, this fourth day of March 1908.

HORACE SANDERSON. RUPERT JOHN ISAAGSON. HENRY ST. JOHN SANDERSON.

Witnesses:

ROBERT EDWIN PEACOOK CRAVEN, EDWIN CRAVEN.

